Allergy-preventive flavonoids from Xanthorrhoea hastilis

Allergy-preventive activity was demonstrated for an extract of resins from Xanthorrhoea hastilis R. BR. in a search for allergy-preventive substances from natural sources. By bioassay-directed fractionation of this plant extract, a new flavanone, 3',5'-dihydroxy-7,4'-dimethoxyflavanone (1), and two new chalcones, 3,5,2'-trihydroxy-4,4'-dimethoxychalcone (2) and 5,2'-dihydroxy-3,4,4'-trimethoxychalcone (3), were isolated together with five known compounds, 5'-hydroxy-7,3',4'-trimethoxyflavanone (4), 3'-hydroxy-7,4'-dimethoxyflavanone (5), liquiritigenin 7-methyl ether (6), 4,2'-dihydroxy-4'-methoxychalcone (7) and sakuranetin (8). The structures of 1, 2 and 3 were elucidated by spectroscopic methods. All of these compounds showed allergy-preventive effects.     

Carbon-13 and proton NMR assignments of a new agathisflavone derivative

The (1)H and (13)C NMR spectra of 5-acetyl-7,4'-dimethoxyflavone-(6-8')-5'-acetyl-7',4'-dimethoxyflavone, a new agathisflavone derivative, were completely assigned on the basis of 1D and 2D NMR techniques.     

Biotransformation of isoflavones by the larvae of the common cutworm (Spodoptera litura)

Biotransformation of the 5,7,4'-trimethoxyisoflavone (1), 6,7,4'-trimethoxyisoflavone (2), and 7,4'-dimethoxyisoflavone (3) by insects, Spodoptera litura was investigated. Compound 1 was transformed to 5-hydroxy-7,4'-dimethoxyisoflavone (4), 7-hydroxy-5,4'-dimethoxyisoflavone (5) and 4'-hydroxy-5,7-dimethoxyisoflavone (6) by S. litura. Compounds 2 and 3 were hardly metabolized by S. litura. This suggested that compound 1 was converted to compounds 4, 5 and 6 by demethylation at the C-5, C-7 and C-4' position, respectively.     

A new hydrochalcone from Miliusa sinensis

A new dihydrochalcone 4',6'-dihydroxy-2',3',4-trimethoxydihydrochalcone (1) along with nine known compounds, pashanone (2), dihydropashanone (3), pinostrobin (4), 5-hydroxy-7,4'-dimethoxyflavanone (5), 5-hydroxy-6,7-dimethoxyflavanone (6), 5-hydroxy-7,8-dimethoxyflavanone (7), 24-methylencycloartane-3β,21-diol (8), liriodenine (9) and 3,5-dihydroxy-7,3',4'-trimethoxyflavone (10), were isolated from the extracts, exhibiting cytotoxic activity (n-hexane and ethyl acetate extracts) of Miliusa sinensis. The structure of (1) was elucidated by the analysis of spectral data (IR, HR-MS, EI-MS, 1D and 2D NMR).     

Total NMR assignments of new [C7-O-C7'']-biflavones from leaves of the limonene-carvone chemotype of Lippia alba (Mill) N. E. Brown

Phytochemical analysis of leaves of the limonene-carvone chemotype of Lippia alba led to the isolation of two biflavonoids with a new structural pattern with an ether linkage: 5,5'-dihydroxy-6,4',6',3',4'-pentamethoxy-[C(7)--O--C(7')]-biflavone (1) and 4',4,5,5'-tetrahydroxy-6,6',3'-trimethoxy-[C(7)--O--C(7')]-biflavone (2). Structural elucidation of the new compounds was established on the basis of spectral data, through the use of 1D NMR and several 2D shift correlated NMR pulse sequences (COSY, HMQC, HMBC and NOESY).     

Two new 5-deoxyflavonoids from Calliandra inermis

Two new 5-deoxyflavonoids, 7,2',3',4'-tetramethoxyflavone (1) and 7,2',3',4'-tetramethoxyflavanone (2) together with a known flavone 7,4'-dimethoxy-3'-hydroxyflavone (3) were isolated from the whole plant of Calliandra inermis. The structures of these new compounds were elucidated by high resolution electron impact mass spectrometry (HR-EI-MS) and 1D and 2D-NMR spectral studies including 1H-1H correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC) and nuclear Overhauser enhancement spectroscopy (NOESY).     

New stilbenoids from Pholidota yunnanensis and their inhibitory effects on nitric oxide production

Six new stilbenoids, a (bibenzyldihydrophenanthrene) ether designated phoyunnanin D (1), a bis(dihydrophenanthrene) ether designated phoyunnanin E (2), and four stilbenes designated phoyunbene A-D (3-6), were isolated from the air-dried whole plant of Pholidota yunnanensis ROLFE. The new compounds were identified as 7-[2-(3-hydroxyphenethyl)-4-hydroxy-6-methoxyphenoxy]-4-hydroxy-2-methoxy-9,10-dihydrophenanthrene (1), 1-[(9,10-dihydro-4-hydroxy-2-methoxy-7-phenanthrenyl)oxy]-4,7-dihydroxy-2-methoxy-9,10-dihydrophenanthrene (2), trans-3,3'-dihydroxy-2',4',5-trimethoxystilbene (3), trans-3,4'-dihydroxy-2',3',5-trimethoxystilbene (4), trans-3,3'-dihydroxy-2',5-dimethoxystilbene (5), and trans-3-hydroxy-2',3',5-trimethoxystilbene (6) based on spectroscopic evidence. Furthermore, the inhibitory effects of compounds 1-6 on nitric oxide production in a murine macrophage-like cell line (RAW 264.7) activated by lipopolysaccharide and interferon-gamma were examined.     

Two new 5-deoxyflavones from Albizia odoratissima

Two new 5-deoxyflavones, 7,8-dimethoxy-3',4'-methylenedioxyflavone (1) and 7,2',4'-trimethoxyflavone (2) together with a known flavone, 7,4'-dimethoxy-3'-hydroxyflavone (3) were isolated from the rootbark of Albizia odoratissima. The structures of these new compounds were elucidated by electrospray ionization mass spectrometry (ESI-MS) and 1D and 2D-NMR spectral studies including (1)H-(1)H correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC) and nuclear Overhauser enhancement spectroscopy (NOESY).     

A new triterpene from Salvia xanthocheila Boiss

From the chloroform extract of the aerial parts of Salvia xanthocheila, one new triterpene, together with two known diterpenes, two known flavonoids and a phytosterol was isolated. On the basis of comprehensive spectroscopic analyses, including electron ionisation mass spectra, 1H-NMR, 13C-NMR, 1-D nuclear Overhauser effect, distortionless enchancement by polarisation transfer, H,H correlation spectroscopy, heteronuclear multiple quantum coherence, rotating frame Overhauser enhancement spectroscopy spectra and comparison with spectral data of known compounds, the structure of new compounds was established as 1β,3β-dihydroxy-olean-9(11),12-dienyl (1). The five known compounds (2-6) were 7α-acetoxyroyleanone, taxodione, salvigenin, apigenin-7,4'-dimethyl ether and β-sitosterol, respectively. These known structures are isolated from the aerial parts of S. xanthocheila for the first time.     

Cholinesterase inhibitory constituents from Onosma hispida

Hispidone, a new flavanone, has been isolated from Onosma hispida and assigned the structure (2S)-5,2'-dihydroxy-7,4',5'-trimethoxyflavanone (1) by spectroscopic methods. In addition, (2S)-5,2'-dihydroxy-7,5'-dimethoxyflavanone (2), benzoic acid (3), and 4-hydroxy benzoic acid (4) are also reported for the first time from this species.     

Isoflavones and rotenoids from the leaves of Millettia brandisiana

A new isoflavone, 4'-gamma,gamma-dimethylallyloxy-5,7,2',5'-tetramethoxyisoflavone, brandisianin A (1), was isolated from the leaves of Millettia brandisiana, along with one synthetically known isoflavone, 7,4'-di-O-prenylgenistein (2) and twelve known compounds. The structures were elucidated on the basis of extensive spectroscopic analysis. Two isolated compounds were tested for anti-inflammatory activity; 12a-hydroxy-alpha-toxicarol (11) showed significant anti-inflammatory activity.     

吲哚啉螺萘并吡喃的合成和时间分辩光谱研究

螺萘并吡喃类化合物是一类重要的有机光致变色化合物,因可用作光敏、光信息和光记录材料,而引起人们的研究兴趣．其中对螺苯并吡喃和螺嗪两类化合物的开环机理有较多的文献报道［１,２］,而对螺萘并吡喃的研究则少得多．我们合成了３个螺萘并吡喃化合物（其中ＳＰ１...     

Structure elucidation and NMR spectral assignments of four neolignan glycosides with enantiometric aglycones from Osmanthus ilicifolius

Four new 8-O-4' type neolignan glycosides with enantiometric aglycones, (7S,8R)-erythro-guaiacylglycerol-beta-O-4'-sinapyl ether 9-O-beta-D-glucopyranoside (1), (7R,8S)-erythro-guaiacylglycerol-beta-O-4'-sinapyl ether 9-O-beta-D-glucopyranoside (2), (7S,8R)-erythro- syringylglycerol-beta-O-4'-sinapyl ether 9-O-beta-D-glucopyranoside (3) and (7R,8S)-erythro- syringylglycerol-beta-O-4'-sinapyl ether 9-O-beta-D-glucopyranoside (4), were isolated from the leaves of Osmanthus ilicifolius. Their structures were established on the basis of NMR, circular dichroism (CD), MS and chemical data. The NMR assignments for the compounds were carried out using (1)H, (13)C, COSY, HMQC, HMBC and NOESY NMR experiments.     

A new isoflavone glycoside from Ceiba pentandra (L.) Gaertner

From the 80% EtOH extract of the bark of Ceiba pentandra (L.) Gaertner, a new isoflavone glycoside was isolated along with known isoflavones, vavain and vavain glucoside. The structure was elucidated by spectroscopic analysis as 5-hydroxy-7,4',5'-trimethoxyisoflavone 3'-O-alpha-L-arabinofuranosyl(1-->6)-beta-D-glucopyranoside.     

A novel cytotoxic C-methylated biflavone,taiwanhomoflavone-B from the twigs of Cephalotaxus wilsoniana

A novel C-methylated biflavone, taiwanhomoflavone-B (1), together with known compounds, 7,4',7"-tri-O-methylamentoflavone, 6-C-methylnaringenin and apigenin-7-O-beta-glucoside were isolated from an ethanolic extract of Cephalotaxus wilsoniana. The structure of 1 was elucidated on the basis of spectroscopic analysis. Taiwanhomoflavone-B is cytotoxic with ED(50) values of 3.8 and 3.5 microg/ml, against KB oral epidermoid carcinoma and Hepa-3B hepatoma cells, respectively.     

4',5'-SUBSTITUTED METHYLANGELICINS: PHOTOCYCLOADDUCTS WITH PYRIMIDINE BASES OF DNA

The isolation and characterization of photocycloadducts with pyrimidine bases from DNA samples irradiated (365 nm) in the presence of four 4',5'-substituted methylangelicins was performed. All these furocoumarins yielded mainly the cis-syn furan-side cycloadduct with thymine. For 4',5'-dimethyl-, 5,4',5'-trimethyl- and 6,4',5'-trimethylangelicin this adduct was accompanied by two pyrone-side adducts ( cis-syn and cis-anti ), whereas the 4,4',5'-trimethyl derivative gave the furan-side adduct with cytosine.
The characterization of the regio- and stereochemistry of the adducts was accomplished by ¹H NOE (nuclear Overhauser effect) and ¹H-¹³C HMBC (heteronuclear multiple-bond connectivity) spectroscopies.
The formation of different cycloadducts in DNA by the various derivatives highlights the role of the methyl groups in determining the regio- and stereochemistry of the cycloaddition.     

Bioconversion of 7-Hydroxyflavanone: Isolation, Characterization and Bioactivity Evaluation of Twenty-One Phase I and Phase II Microbial Metabolites

Microbial metabolism of 7-hydroxyflavanone (1) with fungal culture Cunninghamella blakesleeana (ATCC 8688a), yielded flavanone 7-sulfate (2), 7,4'-dihydroxyflavanone (3), 6,7-dihydroxyflavanone (4), 6-hydroxyflavanone 7-sulfate (5), and 7-hydroxyflavanone 6-sulfate (6). Mortierella zonata (ATCC 13309) also transformed 1 to metabolites 2 and 3 as well as 4'-hydroxyflavanone 7-sulfate (7), flavan-4-cis-ol 7-sulfate (8), 2',4'-dihydroxychalcone (9), 7,8-dihydroxyflavanone (10), 8-hydroxyflavanone 7-sulfate (11), and 8-methoxy-7-hydroxyflavanone (12). Beauveria bassiana (ATCC 7159) metabolized 1 to 2, 3, and 8, flavanone 7-O-β-D-O-4-methoxyglucopyranoside (13), and 8-hydroxyflavanone 7-O-β-D-O-4-methoxyglucopyranoside (14). Chaetomium cochlioides (ATCC 10195) also transformed 1 to 2, 3, 9, together with 7-hydroxy-4-cis-ol (15). Mucor ramannianus (ATCC 9628) metabolized 1 in addition to 7, to also 4,2',4'-trihydroxychalcone (16), 7,3',4'-trihydroxyflavanone (17), 4'-hydroxyflavanone 7-O-α-L-rhamnopyranoside (18), and 7,3',4'-trihydroxy-6-methoxyflavanone (19). The organism Aspergillus alliaceus (ATCC 10060) transformed 1 to metabolites 3, 16, 7,8,4'-trihydroxyflavanone (20), and 7-hydroxyflavanone 4'-sulfate (21). A metabolite of 1, flavanone 7-O-β-D-O-glucopyranoside (22) was produced by Rhizopus oryzae (ATCC 11145). Structures of the metabolic products were elucidated by means of spectroscopic data. None of the metabolites tested showed antibacterial, antifungal and antimalarial activities against selected organisms. Metabolites 4 and 16 showed weak antileishmanial activity.     

Prenylated flavonoids with PTP1B inhibitory activity from the root bark of Erythrina mildbraedii

Phytochemical study on an EtOAc-soluble extract of the root bark of Erythrina mildbraedii resulted in the isolation of six prenylated flavonoids 1-6. Based on physicochemical and spectroscopic analyses, their structures were determined to be new natural products licoflavanone-4'-O-methyl ether (1), 2',7-dihydroxy-4'-methoxy-5'-(3-methylbut-2-enyl)isoflavone (2), and (3R)-2',7-dihydroxy-3'-(3-methylbut-2-enyl)-2',2'-dimethylpyrano[5',6' :4',5']isoflavan (3), along with three known compounds erythrinin B (4), abyssinin II (5), and parvisoflavone B (6). All the isolates, except for compound 4, inhibited PTP1B activity in vitro with IC(50) values ranging from 5.3 to 42.6 microM. This result further suggests that the prenyl group on the B ring of flavonoids plays an important role in suppressing the enzyme PTP1B.     

Antioxidant activity of a new aromatic geranyl derivative of the resinous exudates from Heliotropium glutinosum Phil

Heliotropium glutinosum Phil. (Heliotropiceae) is a resinous bush that grows at a height of 2000 m in Cha?aral, Chile. From the resinous exudates of Heliotropium glutinosum Phil. a new aromatic geranyl derivative: 4-methoxy-3-[(2)-7'-methyl-3'-hydroxymethyl-2',6'-octadienyl] phenol (1) and three flavonoids: 5,3'-dihydroxy-7,4'-dimethoxyflavanone (2), 5,4'-dihydroxy-7-methoxyflavanone (3) and 4'-acetyl-5-hydroxy-7-methoxyflavanone (4) were isolated and their structures were determined. Their antioxidant activity were evaluated using the bleaching of ABTS and DPPH derived cation radical methods and expressed in terms of FRE (fast reacting equivalents) and TRE (total reacting equivalents), where FRE is a good measure of the quick protection of a given compound against oxidants and TRE measures the degree of long-term protection of the antioxidant, or how effective it is against a strong oxidative stress.     

Two new zinniol-related phytotoxins from Alternaria solani

Bioassay-guided purification of the organic crude extract of Alternaria solani resulted in the isolation of three metabolites responsible for causing necrosis on potato leaves. These phytotoxins were identified as 2-(2",3"-dimethyl-but-1-enyl)-zinniol (1), 8-zinniol methyl ether (2). and 8-zinniol methyl ether based on their spectroscopic data (IR, MS, 1H and 13CNMR). Metabolites 1 and 2 have been identified as new phytotoxins structurally related to zinniol (4). Additionally, 5-(3',3'-dimethylallyloxy)-7-methoxy-6-methyl-phthalide and 8-zinniol-2-(phenyl)-ethyl ether (3) were also isolated during the purification process.